This thread title is interesting - the only distinction I would like to suggest is that saving the ECF and saving English Chess, actually mean slightly different things, it is highly possible we can save both, or either, or even none at all..
If we take the big picture view, even before the virus, 'English Chess' was quite healthy - regardless of ECF memberships, the number of people playing online chess in England had never been higher.
However, if we are talking about chess organised under the auspices of our institutions, the ECF, and our Leagues, the picture will be blurred. Institutions, like 4NCL that attract the top teams in England and abroad, will survive no matter what the situation is. Local congresses will be in a quandary, the choice is to 1) wait till they are safe to resume over the board, or 2) simply run them under Government approved conditions (1m apart, more spaced out boards, face masks) with the proviso that players attend at their own risk, and catching the virus is not the organisers' responsibility. The later option is - however - a much more difficult choice for local leagues, who can not realistically run a league saying "teams may enter at their own risk!", especially given the existence of any league ultimately is at the grace of local clubs having a venue.
Some Leagues that are large enough will survive, to paraphrase Varys in Game of Thrones "the big fish eat the little fish, and I just keep paddling".
However, given the first option will be the de facto, for Leagues who's match nights are on a fixed day, say every Thursday, a prolonged suspension of over the board chess, will led to many players opting to do other things on a given weekday. And, once that happens, we may find these players are not all that interested in coming back to over-the-board chess, even when it resumes. (This scenario may be less severe for Leagues where the match nights are not fixed on a particular weekday, as those who wish to return will always be able to find a day where they can play chess)
Nevertheless, local leagues have to be conscious that if they don't act for too long, there may not be a league to come back to..
Delegate for Coventry & District, and Leamington & District
Vice Chair @ Coventry and District Chess League | former-President @ Warwick University Chess
Celebrating 100 Years of the Coventry & District Chess League 1919-2019